Furnaces according to CQI-9

Why are furnaces designed according to CQI-9 and what use is that to me as a user?

Manufacturers of products are not only interested in low-cost production, but above all in a consistently high quality of their products. This includes, of course, and in particular, reproducible heat treatment at a high level and this is primarily dependent on whether the products are always heated up at the same rate and always brought to the same final temperature. In order to achieve this, the furnace used must have comparable temperatures at all positions in its working chamber and this is precisely specified in DIN 17052-1, CQI-9 and AMS 2750.


The CQI-9 is not a German standard, but a standard created by the AIAG for the automotive industry and its suppliers. This standard not only specifies the quality of the oven – similar to DIN 17052 – in terms of uniformity, but also the regular verification of this through so-called SAT and TUS measurements. These specify how accurate the temperature uniformity must be in the non-loaded working chamber or on the product during the steady state and how this must be determined, as well as the exact structure and accuracy of the measuring chain and the regular repetition of the measurements.

This means that either the empty furnace is heated up to its working temperature and then the uniformity is measured and documented at several points in the furnace (depending on the size, the number of points varies) or that a representative product is fitted with several sensors and then heated up to the working temperature.

The CQI-9 specifies the position and quality of the sensors or the entire measuring chain, as well as a specification of the maximum deviation.

Example: A furnace for solution annealing or ageing aluminium must achieve a uniformity of +-5K; a furnace for annealing aluminium +-15K.

Since Airtec furnaces achieve a uniformity of +-5K as standard, you are always safe on the road with our products in the automotive sector. If you have special, higher requirements, please do not hesitate to ask us – we are also happy to supply equipment that meets even higher requirements.

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